[请教]BIOS地址映射?

暴雪

原512K的ROM，现换了一个1M的ROM，windows下在 0xFFF0 0000~0xFFF7 FFFF 可以看到追加的512K的内容。
& q2 Z. @1 p. y. p( ]1 I7 ]% V但在启动计算机时(BIOS没有初始化计算机），无法访问追加的512K的ROM。
: U( q) ?1 o, Z' |. L- J9 D(可以访问原512K的ROM 0xFFF8 0000~0xFFFF FFFF)

我的计算机用的是intel的ICH7南桥。
2 N4 u) |: D7 C) |1 w在手册上
7 O% k7 U: J! bFWH_SEL2—Firmware Hub Select 2 Register (LPC I/F—D31:F0)
6 k7 [* Q9 H% X" s' {0 D0 L. WFWH_70_IDSEL — R/W. IDSEL for two, 1-M Firmware Hub memory ranges.
0 g7 D8 H; t* v$ [4 nThe IDSEL programmed in this field addresses the following memory ranges:
FF70 0000h – FF7F FFFFh
% O+ d9 P0 G* T5 B8 @5 [FF30 0000h – FF3F FFFFh
1 `1 F6 Y# x6 `在这里 IDSEL 如何理解。
, A, \% R8 C& \FWH_DEC_EN1—Firmware Hub Decode Enable Register
(LPC I/F—D31:F0)
FWH_70_EN — R/W. Enables decoding two 1-M Firmware Hub memory ranges.
3 H. `/ k7 D! T" ]4 l" o% C. y# e9 E0 = Disable.
% f9 l6 P, R2 i4 a! o6 j  K0 F1 = Enable the following ranges for the Firmware Hub
FF70 0000h – FF7F FFFFh
& C2 @3 x; C$ l1 Z6 I9 q! Q9 T3 M3 wFF30 0000h – FF3F FFFFh
% L/ O9 t3 |& d  ^# q1 E+ D除了上面的数据区域，还有其它的数据区域控制ROM到内存地址的映射吗？

; x/ U& U- \* T% ~$ K1 ^/ O9 `  u- D谢谢大家了！！！

xtdumpling

IDSEL是LPC spec的一个信号(Device Select),
This one clock field is used to indicate which of multiple Firmware components is being selected.
/ G; P! w. |- \5 u) j& qThe four bits transmitted over AD[3:0] during this clock are compared with values strapped onto
pins on the Firmware component. If there is a match, the Firmware component will continue to
decode the cycle to determine which bytes are requested on a read or which bytes to update on a
write. If there isn’t a match, the Firmware component may discard the rest of the cycle and go into
a standby power state.
8 v4 A4 k& n4 I; }* \5 A4 J# p* m: G
详见LPC spec:
3 H$ C3 i! ]$ H' A. J, f8 M6 fhttp://www.intel.com/design/chipsets/industry/25128901.pdf
' j! }3 F+ {- x; B7 a
/ E7 v  _* T. U在ICH 7 中似乎就这几个吧(FWH_SEL1,FWH_SEL2,FWH_DEC_EN1,BIOS_CNTL),据我现在知道的.